pre cut cars

[Utecharger]

Well last time we all spoke I was telling you how we had placed 1st and 2nd in the derby and how excited we were. Well that was last year.

Last night we had our derby and we took a miserable 8th place. But that is not why I am upset. This years car beat the times from last years, on the same track, by an average of 3/100th's. We used a tungsten disk this year and I was pretty sure we had a winner. This is where I have a question? What is it about those store bought, pre-cut cars that make them so much better/faster? And yes I know they are store bought because I personally assisted with 3 of them and was there when they pulled them out of the bag. In the past, when I was the leader, I stated that pre-cut cars were not allowed but I am no longer in charge. There were 6 store cars that came out ahead of ours and even though we had great times, as compared to last year, four of these cars were constantly finishing in the 3.0 range. The owner of the track says he hardly ever sees cars get below the 3.1's and never more than 1 from the same pack. He was amazed himself.

So this is where I come to you my Pinewood bretheren. What is it about these pre cut cars that make them so fast? 3 of the 4 in the final were pre cut and I am worried that I am not going to be able to keep up in the years to come. My older boys have trophies lining their walls but now I worried that I wont be able to assist my younger boys in winning. The younger boys pretty much expect the same winning tradition and I will admit I saw the look of disapointment on their faces last night and could read the "this is not good for the future" in thier little minds.

Any advice would be greatly appreciated.

[KyDerbyDad]

I doubt that a pre-cut body has much to do with the speed. It sounds to me like maybe the fast cars where running the new wheels and the kit you used had the old style ones (this year their where a mixture of old/new in the standard kit). The BSA pre-cut kits from Revell all had the newer wheels.

[psycaz]

The new wheels do make a huge difference. .02 I believe faster than last years wheels.

That right there could be where things changed. Times I have been seeing are simply amazing this year.

[FatSebastian]

What is it about those store bought, pre-cut cars that make them so much better/faster?

Utecharger, can you elaborate on what you mean by "pre-cut" cars? Are you referring to the BSA-authorized Revell kits, or something available from hobby shops, or derby suppliers, or...? What specific designs are you referencing? (I have a hard time imagining that Revell's skateboard and luge rider terribly fast - I've seen those race and they placed poorly.)

[JSG]

I doubt it had much to do with being a pre-cut car body. I would look more closely at the build details of your cars.

[Utecharger]

This was definately not the case. We had bought 4 on the new boxes and I was even able to find 4 wheels of the same mold to put on this car.

What amazes me is the jump in competition. for 3 straight years it was always the same kids getting roughly the same 3.1's to 3'2's times and that determined the winner. This year we had kids getting 3.06's to 3.08's and they were all, but 1, pre cut cars. I know all the secrets, trust me I do. That is why this is so frustrating. Am I doomed to mediocrity now? I refuse to buy a pre-cut car but I dont know what else to do.

Could it be my weight ratio? I know they say that a 4-1 is usually the best (4 oz in back, 1 oz in the front). Maybe since ours was 4.3 to .7 that was our downfall? but it wasn't poping a wheelie by any means. I had moved the back wheels so that wouldn't be a problem. maybe my wheels were too far apart? Wow this is all very frustrating!!!

Four of the bodies were bought at a hobby shop and I know the other 2 were bought online.

What is the hardest for me is that for years we have been accused of cheating. now that we are no longer in charge and we got our rear ends handed to us it looks even more like we were cheating when we were the leaders.

P.S. the kid who took 1st is a neighbor of mine and I was able to look at his car before and after the race. I performed a finger spin count with his tires and he was only around 18-22 seconds. All our tires were around 30 so I know our axels and wheels had to have been better prepared? So what made the difference?

[pwrd by tungsten]

Precut cars will have better slots and (if drilled) better drilled holes.

I use The Block to drill holes and they are very straight. I use canted holes on the rear and straight holes on the front. and then bend the DFW axle and create positive cant on the DFW. Your weight dist sounds good. Make sure you have at least 3.5 ounces of solid disc in the car...

[FatSebastian]

All our tires were around 30 so I know our axels and wheels had to have been better prepared? So what made the difference?

Alignment? Extended wheelbase? CoM location? Rail-riding?

There are many details missing, Utecharger. For example, you said you used a tungsten disk this year; it can be difficult to put the disk in the optimum spot unless you move the wheels back. It may then necessary to trim the axles, which in turns makes a car harder to align.

I could agree with other who have speculated that pre-cut bodies likely offered no advantage, but again, details are missing. My experience has been that those who use pre-cuts are those who don't know as much about what to do, and as a result those cars tended to be slower.

[JSG]

P.S. the kid who took 1st is a neighbor of mine and I was able to look at his car before and after the race. I performed a finger spin count with his tires and he was only around 18-22 seconds. All our tires were around 30 so I know our axels and wheels had to have been better prepared? So what made the difference?

Sorry but I think you're getting a little carried away with this.

[Utecharger]

P.S. the kid who took 1st is a neighbor of mine and I was able to look at his car before and after the race. I performed a finger spin count with his tires and he was only around 18-22 seconds. All our tires were around 30 so I know our axels and wheels had to have been better prepared? So what made the difference?

Sorry but I think you're getting a little carried away with this.

Since we are friends he had me over to assist him and asked me to look at his wheels. It wasn't as if I snatched up random cars to see how good their wheels spun.

As for the other information my CoG was about 2 inches from the back. It was not a rail rider and I used the pro-body tool to drill the holes. The front and rear wheels were about 1/2 inch from the ends. The hole for the tungsten disk was placed at the top of the car near the back. The disk slightly came up above the top surface of the car. I did this so it wouldn't interfer with the axels. Maybe that was part of my problem?

[FatSebastian]

As for the other information my CoG was about 2 inches from the back. It was not a rail rider and I used the pro-body tool to drill the holes. The front and rear wheels were about 1/2 inch from the ends. [...] Maybe that was part of my problem?

A CoM placement of 1.5" in front of the rear axles sounds far from optimal.

[*5 J's*]

30 second spin time certainly sounds like the old wheels. I wouldn't expect to see the new wheels spin that long. We haven't finished our cars so I don't have any actual data yet.

[psycaz]

As for the other information my CoG was about 2 inches from the back. It was not a rail rider and I used the pro-body tool to drill the holes. The front and rear wheels were about 1/2 inch from the ends. [...] Maybe that was part of my problem?

A CoM placement of 1.5" in front of the rear axles sounds far from optimal.

I'll second this as at least part of it.

If you can look at the other car again, compare what your car stats are as compared to it.

Com placement, wheelbase and wheel placement. Railrunning with their car? Running on threee wheels?

Stats on the car(s) would help up point you in the right direction.

[JSG]

1.5 " COM is what lost the race. Trust me.....

[Utecharger]

As for the other information my CoG was about 2 inches from the back. It was not a rail rider and I used the pro-body tool to drill the holes. The front and rear wheels were about 1/2 inch from the ends. [...] Maybe that was part of my problem?

A CoM placement of 1.5" in front of the rear axles sounds far from optimal.

Maybe I miss spoke. the CoG was only about 1/4 to 1/2 inches in front of the rear wheels. I would have to go home and measure to be exact but I know it wasn't 1.5". I know that is no bueno.

This is one of the cars that I assisted with that took 3rd. We drilled 6 holes on the sides from the very back to just about where the windsheild is and placed those round cylinder weights, cut in half, in them. http://www.pinewoodpro.com/p/060255.html" target="_blank

This was another one that did very well with the weights placed in it a similar way. http://www.pinewoodpro.com/images/bulle ... right.jpeg" target="_blank

the thing is the first link I posted I helped this Father and his son from the start to the finish. We had placed our weights in our cars like this in the past but opted for the disk this year. he didn't do anything special to it yet it tore up the track.

As for the 30 second finger spin on the new tires, it is very possible. I know these are the new tires as I have compared them to last years.